Achieving Extreme Light Intensities using Optically Curved Relativistic Plasma Mirrors

This Letter proposes a realistic implementation of the curved relativistic mirror concept to reach unprecedented light intensities in experiments. The scheme is based on relativistic plasma mirrors that are optically curved by laser radiation pressure. Its validity is supported by cutting-edge three-dimensional particle-in-cell simulations and a theoretical model, which show that intensities above ${10}^{25}\mathrm{W}{\mathrm{cm}}^{-2}$ could be reached with a 3 PetaWatt (PW) laser. Its very high robustness to laser and plasma imperfections is shown to surpass all previous schemes and should enable its implementation on existing PW laser facilities.

Figure 1

3D PIC simulation of PM focusing for optimal parameters $\theta =45°$, $L={\lambda }_L/8$ and normalized laser amplitude $a_0=75$. (a) Sketch of the laser-PM interaction and (b) reflected field intensity vs distance $z$ to the PM. (c) and (e) respectively show one optical laser cycle only of the spatiotemporal intensity profile $I(x,t)$ of the reflected field at PM plane and PM focus. (d) and (f) respectively show the reflected beam spatial intensity profile $I(x,y)$ at PM plane and PM focus. On (c)–(f) the color scale represents light intensity in units of $\mathrm{W}{\mathrm{cm}}^{-2}$.

Figure 2

Effect of PM focusing on harmonic spectra. In all plots, red lines correspond to simulation results obtained for a 3 PW incident laser ($a_0=75$). The black lines correspond results obtained for a 100 TW laser case ($a_0=2$). In all cases, $L=\lambda /8$ was used. (a) Harmonic spectra of the reflected field in the plane of the PM obtained from 2 PIC simulations. (b) Source sizes of harmonic beams obtained from 2D PIC simulations. (c) Harmonic spectra at PM focus deduced from panel (a) using equation (4) and ${\delta }_p=\lambda /8$. Red squares are harmonic peak maxima obtained from the 3D simulation of Fig. 1.

Figure 3

Intensity gain map of $\mathrm{\Gamma }$ as a function of scale length $L$ and amplitude $a_0$ for a fixed $\theta =45°$ obtained from two-dimensional (2D) PIC simulations. The side panels are line-outs of the gain map along the white dashed lines. The blue curve represents $\mathrm{\Gamma }$ vs prepulse delay $\tau$, with nonisothermal preplasma profiles obtained from hydrodynamic simulations (see SM7).

Figure 4

Evolution of $\mathrm{\Gamma }$ with the PM denting ${\delta }_p$ assuming fixed parameters ($a_0=75$, $L=\lambda /8$, $\theta =45°$) yielding constant harmonic spectra. The dashed line shows the reference case of ${\delta }_p=0.125\lambda$ corresponding to the case of Fig. 1 and 2. Red point: case of the BELLA PW laser (see text).